Quick depth adjustment for parallel arm openers

ABSTRACT

A parallel arm furrow opener assembly defines upper and lower front pivot axes and upper and lower rear pivot axes oriented horizontally and perpendicular to a travel direction. A furrow opener and a packer wheel are attached to a rear link of the assembly. In operation the furrow opener and the packer wheel are in fixed positions with respect to the rear link member, and a bias element is operative to exert a downward bias force on the furrow opener assembly. A front pivot line connecting the upper and lower front pivot axes is parallel to a rear pivot line connecting the upper and lower rear pivot axes, and the front and rear pivot lines are oriented at a pivot angle with respect to a vertical orientation, and the pivot angle is adjustable to vary a furrow depth of the furrow.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and benefit of CA Serial No.2,968,181, filed May 24, 2017, the contents of which are incorporated byreference in their entirety for all purposes.

FIELD OF THE INVENTION

This disclosure relates to the field of agricultural implements and inparticular a seeding implement with parallel arm furrow openerassemblies where the depth of penetration into the soil of the furrowopeners can be adjusted quickly.

BACKGROUND

Trailing arm furrow opener assemblies are well known in the agriculturalindustry. These assemblies are spaced across the width of a seedingimplement and each comprises a lengthy arm that is pivotally attached atthe front end thereof to the implement frame about a horizontal pivotaxis oriented perpendicular to the operating travel direction such thatthe arm can pivot up and down with respect to the frame. A packer wheelis mounted to a rear end of the arm and one or more furrow opener shanksextend downward from the arm forward of the packer wheel. A bias elementsuch as a spring or hydraulic cylinder exerts a downward bias force onthe arm to push the furrow opener mounted on the bottom of the shankinto the soil to create a furrow, and the furrow depth is set by therelative positions of the packer wheel and furrow opener.

Such a trailing arm furrow opener assembly is disclosed for example inU.S. Pat. No. 7,159,523 to Bourgault et al. particularly in FIG. 1thereof. Similarly U.S. Pat. No. 5,396,851 to Beaujot discloses such atrailing arm with two furrow opener shanks with knife type furrowopeners attached to the bottoms thereof and configured to make twoslightly laterally spaced furrows, one for seeds and the other forfertilizer. U.S. Pat. No. 5,609,114 to Barton discloses a similartrailing arm with one or two disc type furrow openers mounted to thearm.

Seeding operations require that a consistent furrow depth be maintained.The desired seeding depth will also vary depending on the crop beingplanted, with a deeper furrow depth for larger seeds such as corn andpeas and a shallower furrow depth for smaller seeds such as canola. Inmany common trailing arm type seeding implements the frame is mounted onfixed wheels so the distance from the frame to the ground surface isconstant. The furrow opener assemblies are then pivoted about the frontarm axis to move between an operating position engaged in the ground anda transport position above the ground. The furrow depth is adjusted bymoving each packer wheel up or down with respect to the correspondingfurrow opener. A typical seeding implement may have 80 or more furrowopener assemblies, and changing the furrow depth is a time-consumingoperation.

Maintaining consistent furrow depth is problematic with trailing armfurrow opener assemblies with a single arm such as that of Bourgault,Barton, and Beaujot in uneven terrain where the distance between theframe and the ground varies. As the vertical distance of the frame abovethe ground varies the trailing arm moves up and down about its pivotalattachment to the seeder and the angle of the trailing arm changes suchthat the distance from the middle portion of the arm, where the furrowopener is attached, to the ground varies, and thus the actual depth ofthe seed furrow varies.

While this property is problematic for furrow depth consistency inuneven terrain, it is also useful for providing a relatively quick wayto change the furrow depth when changing from one crop to another. Theimplement frame may be mounted on movable wheels so the distance betweenthe frame and the ground surface can be adjusted, and such an adjustmentof the frame height also changes the furrow depth.

To improve the consistency of the furrow depth Bourgault et al. alsodisclose, in FIGS. 5-9 of U.S. Pat. No. 7,159,523, a trailing arm formedby upper and lower parallel arms of equal length. Front ends of the armsare pivotally connected to a front link member fixed to the implementframe, and rear ends of the arms are pivotally connected to a rear linkmember. Such a parallel link assembly has the property that the rearlink member is maintained in a constant horizontal and verticalorientation through the vertical range of motion without tilting forwardor rearward. The front link member thereof is fixed to the implementframe and the rear packer wheel and the furrow opener are fixed to therear link member. Thus, as the packer wheel moves up and down relativeto the frame in uneven terrain, the packer wheel and furrow opener movetogether vertically and so the furrow depth is maintained at a constantdepth. In these parallel arm assemblies the furrow depth is adjusted bythe time consuming operation of moving each packer wheel up or down withrespect to the corresponding furrow opener.

A further issue with seeding implements is the fore and aft presentationangle of the furrow opener with respect to the ground surface. Furrowopeners typically include a pointed front end or tip that is oriented toengage the soil and draw the furrow opener into the soil. The producttube deposits agricultural product generally behind the tip after thefurrow has been formed and before the soil moved aside to create thefurrow can drop back into the furrow so that the product is at thebottom of the furrow, and the soil falls back on top of the product.Some furrow openers make more than one furrow, with product dividedbetween the furrows, or with different product directed to each furrow.

Thus, as the fore and aft presentation angle changes, the angularrelationship between the furrow opener and the soil, which dictates theform of the furrow made, and the relationship between the furrow openerand the product tube, which dictates the location of the agriculturalproduct in the furrow, changes as well. In a conventional trailing armfurrow opener assembly with a single arm, as the arm moves up and downwith respect to the frame, the presentation angle changes.

Parallel arm assemblies fix the fore and aft presentation angle of thefurrow openers with respect to the ground as the furrow opener moves upand down in uneven terrain such that the presentation angle does notchange.

U.S. Pat. No. 7,549,481 to Lung et al. addresses the issue of providinga consistent presentation angle by providing a parallel arm assemblywhere only the furrow opener is attached to the rear link member and thepacker wheel is attached to a rear end of one of the upper and lowerarms of the parallel arm assembly. In this arrangement the parallel armassembly moves up and down in the same manner as a single arm furrowopener assembly, with the furrow depth varying in uneven terrain,however the presentation angle is maintained constant as the armassembly moves up and down. As in a conventional single arm assembly,depth adjustment can be accomplished by raising and lowering theimplement frame with respect to the ground.

It is also known to add remote actuation to each trailing arm opener toadjust the position of the packer wheel to change the depth of thefurrow as disclosed in United States Published Patent Application Number2011/0282556 of Klenz et al. However, this solution to improve the easeand efficiency of depth adjustment on each opener is expensive and addsreliability concerns due to the added electronics in a somewhat harshoperating environment.

BRIEF SUMMARY

The present disclosure provides a seeding apparatus that overcomesproblems in the prior art.

In a first embodiment the present disclosure provides a seedingapparatus comprising an implement frame mounted on wheels for travelover the ground in an operating travel direction and a furrow openerassembly extending rearward from a lateral frame member of the implementframe. The furrow opener assembly comprises a front link member fixed tothe lateral frame member, and upper and lower parallel arm memberspivotally attached at front ends thereof to the front link member aboutcorresponding upper and lower front pivot axes oriented substantiallyhorizontally and perpendicular to the operating travel direction, andpivotally attached at rear ends thereof to a rear link member aboutcorresponding upper and lower rear pivot axes oriented substantiallyparallel to the front pivot axes. A furrow opener bracket is attached tothe rear link member, and a furrow opener is attached to a lower portionof the furrow opener bracket, and the furrow opener is operative to forma furrow when a bottom end thereof is engaged in the ground. A packerwheel arm is attached to the rear link member and a packer wheel isrotatably attached to a rear end of the packer wheel arm. In operationthe furrow opener and the packer wheel are in fixed positions withrespect to the rear link member, and a bias element is operative toexert a downward bias force on the furrow opener assembly. A raisingmechanism is operative to move the furrow opener assembly between alowered operating position and a raised transport position. A frontpivot line connecting the upper and lower front pivot axes issubstantially parallel to a rear pivot line connecting the upper andlower rear pivot axes, and the front and rear pivot lines are orientedat a pivot angle with respect to a vertical orientation, and the pivotangle is adjustable to vary a furrow depth of the furrow.

In a second embodiment the present disclosure provides a seedingapparatus comprising an implement frame mounted on wheels for travelover the ground in an operating travel direction, and a rockshaftrotatably attached to a lateral frame member of the implement frameabout a lateral rotation axis, and a lock mechanism operative to securethe rockshaft at a selected rotational position. A furrow openerassembly extends rearward from the lateral frame member and therockshaft and comprises a frame parallel arm assembly comprising a frontframe link member fixed to the lateral frame member and defining upperand lower front frame pivot axes, and a rear frame link member definingupper and lower rear frame pivot axes, wherein the frame pivot axes arearranged so that a front frame pivot line between the upper and lowerfront frame pivot axes and a rear frame pivot line between the upper andlower rear frame pivot axes are substantially parallel and ofsubstantially equal length, and a rockshaft parallel arm assemblycomprising a front rockshaft link member fixed to the rockshaft anddefining upper and lower front rockshaft pivot axes and a rear rockshaftlink member defining upper and lower rear rockshaft pivot axes, whereinthe rockshaft pivot axes are arranged so that a front rockshaft pivotline between the upper and lower front rockshaft pivot axes and a rearrockshaft pivot line between the upper and lower rear rockshaft pivotaxes are substantially parallel and of substantially equal length. Afurrow opener bracket is attached to the rear rockshaft link member andconnected during operation to the rear frame link member with a furrowopener attached to a lower portion of the furrow opener bracket, thefurrow opener operative to form a furrow when a bottom end thereof isengaged in the ground. A packer wheel arm is attached to the rear framelink member and the rear rockshaft link member and a packer wheel isrotatably attached to a rear end of the packer wheel arm. A bias elementis operative to exert a downward bias force on the furrow openerassembly, and a raising mechanism is operative to move the furrow openerassembly between a lowered operating position and a raised transportposition. A furrow depth of the furrow is adjusted from a first depth toa second depth by rotating the rockshaft from a first rotationalposition to a second rotational position, and a fore and aftpresentation angle of the furrow opener is maintained at a constantangle.

In a third embodiment the present disclosure provides a method offorming a furrow in a ground surface. The method comprises connecting afront link member of a parallel arm assembly to a lateral frame memberof an implement frame mounted on wheels for travel over the groundsurface in an operating travel direction such that the parallel armassembly extends rearward from the lateral frame member; wherein a frontpivot line connects upper and lower front pivot axes of the parallel armassembly and is substantially parallel to a rear pivot line connectingupper and lower rear pivot axes of the parallel arm assembly, and thefront and rear pivot lines are oriented at a pivot angle with respect toa vertical orientation; connecting a furrow opener bracket to a rearlink member of the parallel arm assembly, and attaching a furrow openerto a lower portion of the furrow opener bracket, wherein the furrowopener is operative to form the furrow when a bottom end thereof isengaged in the ground surface; supporting the rear link member with apacker wheel rearward of the furrow opener; exerting a downward biasforce on the parallel arm assembly such that the furrow opener engagesthe ground surface; moving the implement frame across the ground surfaceto create the furrow; orienting the pivot angle at a first pivot angleto form the furrow with a first furrow depth, and orienting the pivotangle at a second pivot angle to form the furrow with a second furrowdepth different from the first furrow depth.

The present disclosure provides a seeding apparatus with trailing armfurrow opener assemblies where the depth of the furrow formed by thefurrow openers can be quickly changed to suit different crops and soilconditions. The depth of penetration of all the furrow openers on aseeding implement can be adjusted at the same time. In some embodimentsthe presentation angle of the furrow opener with respect to the groundsurface can be maintained at a constant desired angle.

DESCRIPTION OF THE DRAWINGS

While the invention is claimed in the concluding portions hereof,preferred embodiments are provided in the accompanying detaileddescription which may be best understood in conjunction with theaccompanying diagrams where like parts in each of the several diagramsare labeled with like numbers, and where:

FIG. 1 is a schematic top view of an embodiment of the seeding apparatusof the present disclosure;

FIG. 2 is a side view of the embodiment of FIG. 1 where the front andrear ends of the implement frame are the same distance above the ground;

FIG. 3 is a side view of the embodiment of FIG. 1 where the front end ofthe implement frame is higher than the rear end thereof;

FIG. 4 is a side view of the embodiment of FIG. 1 where the front end ofthe implement frame is lower than the rear end thereof;

FIG. 5 is a schematic top view of an alternate embodiment of the seedingapparatus of the present disclosure;

FIG. 6 is a schematic side view of a furrow opener assembly of theembodiment of FIG. 5 shown in a first position forming a furrow with afirst depth;

FIG. 7 is a schematic side view of a furrow opener assembly of theembodiment of FIG. 5 shown in a second position forming a furrow with asecond depth greater than the first depth;

FIG. 8 is a schematic top view of a further alternate embodiment of theseeding apparatus of the present disclosure;

FIG. 9 is a schematic side view of a furrow opener assembly of theembodiment of FIG. 8 shown in a first position forming a furrow with afirst depth;

FIG. 10 is a schematic side view of a furrow opener assembly of theembodiment of FIG. 8 shown in a second position forming a furrow with asecond depth greater than the first depth;

FIG. 11 is a schematic side view of an alternate furrow opener assemblyfor use with the embodiment of FIG. 8 shown in a first position forminga furrow;

FIG. 12 is a schematic side view of the alternate furrow opener assemblyof FIG. 11 shown with the furrow opener above the ground and thehydraulic cylinder moving the furrow opener assembly toward the raisedposition;

FIG. 13 is a schematic side view of a further alternate furrow openerassembly for use with the embodiment of FIG. 8 shown in a first positionforming a furrow with a first depth;

FIG. 14 is a schematic side view of the furrow opener assembly of FIG.13 shown in a second position forming a furrow with a second depth lessthan the first depth.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIGS. 1-4 schematically illustrate an embodiment of a seeding apparatus1 of the present disclosure comprising an implement frame 3 mounted onwheels 5 for travel over the ground 7 in an operating travel directionT. A plurality of furrow opener assemblies 9 is mounted on the implementframe 3. Each furrow opener assembly 9 extends rearward from a lateralframe member 11 of the implement frame 3 and comprises a front linkmember 13 fixed to the lateral frame member 11, and upper and lowerparallel arm members 15A, 15B are pivotally attached at front endsthereof to the front link member 13 about corresponding upper and lowerfront pivot axes UFA, LFA oriented substantially horizontally andperpendicular to the operating travel direction T, and pivotallyattached at rear ends thereof to a rear link member 17 aboutcorresponding upper and lower rear pivot axes URA, LRA orientedsubstantially parallel to the front pivot axes UFA, ULA.

A furrow opener bracket 19 is attached to the rear link member 17, and afurrow opener 21 is attached to a lower portion of the furrow openerbracket 19. The furrow opener 21 is operative to form a furrow 23 when abottom end thereof is engaged in the ground 7. A packer wheel arm 25 isattached to the rear link 17 and a packer wheel 27 is rotatably attachedto a rear end of the packer wheel arm 25. The vertical position of thepacker wheel 27 with respect to the furrow opener 21 may be adjustableto provide a wider range of furrow depth however during a seedingoperation the furrow opener 21 and the packer wheel 27 are in fixedpositions with respect to the rear link member 17. The furrow openersschematically illustrated in this disclosure are, for simplicity ofillustration, shown as knife or hoe type openers however it will berecognized that a disc opener could also be rotatably mounted to thelower portion of the furrow opener brackets illustrated herein.

Thus the furrow openers assembly 9 includes a parallel arm assembly withthe front link 13 fixed to the implement frame 3 and the furrow opener21 and packer wheel 27 both fixed to the rear link 17. As known in theart, this furrow opener assembly 9 can pivot up and down with respect tothe implement frame 3 and the depth of the furrow 23 created by thefurrow opener 21 will remain constant.

A bias element, typically a hydraulic cylinder 29 as illustrated, isoperative to exert a downward bias force DBF on the furrow openerassembly 9. The hydraulic cylinder 29 typically also provides theraising mechanism operative to move the furrow opener assemblies 9between a lowered operating position 9A and a raised transport position9B as schematically illustrated in FIG. 4.

A front pivot line FPL connecting the upper and lower front pivot axesUFA, LFA is substantially parallel to a rear pivot line RPL connectingthe upper and lower rear pivot axes URA, LRA, and the front and rearpivot lines FPL, RPL are oriented at a pivot angle PN with respect to avertical orientation V, and the pivot angle PN is adjustable to vary afurrow depth of the furrow 23.

In the illustrated apparatus 1, the pivot angle is adjusted byselectively tilting a front end 3F of the implement frame 3 up or downwith respect to a rear end 3R of the implement frame 3 to adjust thepivot angle PN. The implement frame 3 is mounted on front wheels 5F andrear wheels 5R, and the front wheels 5F and the rear wheels 5R are movedselectively up or down with respect to the implement frame 3 to tilt thefront end 3F of the implement frame 3 up or down with respect to therear end 3R of the implement frame 3.

FIGS. 2-4 schematically illustrate this tilting of the implement frame 3and the resulting change in the pivot angle PN. In FIGS. 2-4 the linerepresenting the ground 7 is placed at a fixed location with respect tothe implement wheels 5 and the packer wheels 27 to illustrate thechanges in the vertical position of the bottom of the furrow openers 21with respect to the ground 7, and with respect to the implement wheels 5and the packer wheels 27 which follow the ground.

In FIG. 2 the implement frame 3 is oriented substantially level with alllateral frame members 11 the same distance above the ground surface 7,and the front pivot line FPL oriented at a first pivot angle PNA. Thebottom ends of the furrow openers 21 are on the line 7 representing theground surface.

In FIG. 3 the front wheels 5F are moved downward and the rear wheels 5Rare moved upward with respect to the implement frame 3 by wheelactuators 31 to tilt the front end 3F of the implement frame 3 up withrespect to the rear end 3R thereof compared to the level orientation ofFIG. 2. Tilting the front end 3F of the implement frame 3 up withrespect to the rear end 3R thereof moves the upper front pivot axis UFArearward with respect to the lower front pivot axis LFA and the frontpivot line FPL is oriented at a second pivot angle PNB that is greaterthan the first pivot angle PNA. In FIG. 3 the bottom ends of the furrowopeners 21 are slightly above the line 7 representing the groundsurface, indicating the furrow openers 21 have been raised with respectto the ground surface 7 and with respect to the implement wheels 5 andthe packer wheels 27 which follow the ground, and thus the depth of thefurrow 23 is decreased.

In FIG. 4 the front wheels 5F are moved upward and the rear wheels 5Rare moved downward with respect to the implement frame 3 by wheelactuators 31 to tilt the front end 3F of the implement frame 3 down withrespect to the rear end 3R thereof compared to the level orientation ofFIG. 2. Tilting the front end 3F of the implement frame 3 down withrespect to the rear end 3R thereof moves the upper front pivot axis UFAforward with respect to the lower front pivot axis LFA and the frontpivot line FPL is oriented at a third pivot angle PNC that is less thanthe first pivot angle PNA. In FIG. 4 the bottom ends of the furrowopeners 21 are slightly below the line 7 representing the groundsurface, indicating the furrow openers 21 have been lowered with respectto the ground surface 7 and with respect to the implement wheels 5 andthe packer wheels 27 which follow the ground, and thus the depth of thefurrow 23 is increased.

In the illustrated apparatus 1 both the front and rear wheels 5F, 5R aremoved up and down however it is contemplated that tilting of theimplement frame 3 could be accomplished by moving only the front wheels5F or only the rear wheels 5R. In a typical seeding operation a desiredfurrow depth change might be only 0.5 inches or less and it can be seenthat tilting the implement frame 3 only slightly may accomplish thedesired change.

FIGS. 5-7 schematically illustrate an alternate apparatus 101 of thepresent disclosure comprising an implement frame 103 mounted on wheels105 for travel over the ground 107 in an operating travel direction T.In the apparatus 101 front and rear wheels 105F, 105R support theimplement frame 103 at a constant height above the ground surface 107.Furrow opener assemblies 109 are mounted on the implement frame 103 andeach furrow opener assembly 109 extends rearward from a lateral framemember 111 of the implement frame 103 and comprises a front link member113 fixed to the lateral frame member 111, and upper and lower parallelarm members 115A, 115B are pivotally attached at front ends thereof tothe front link member 113 about corresponding upper and lower frontpivot axes UFA, LFA oriented substantially horizontally andperpendicular to the operating travel direction T, and pivotallyattached at rear ends thereof to a rear link member 117 aboutcorresponding upper and lower rear pivot axes URA, LRA orientedsubstantially parallel to the front pivot axes UFA, ULA.

A furrow opener bracket 119 is attached to the rear link member 117, anda furrow opener 121 is attached to a lower portion of the furrow openerbracket 119. The furrow opener 121 is operative to form a furrow 123when a bottom end thereof is engaged in the ground 107. A packer wheelarm 125 is attached to the rear link 117 and a packer wheel 127 isrotatably attached to a rear end of the packer wheel arm 125. Therelative position of the packer wheel 127 and furrow opener 121 may beadjustable to provide a wider range of furrow depth however during aseeding operation the furrow opener 121 and the packer wheel 127 are infixed positions with respect to the rear link member 117.

In the alternate apparatus 101, the lateral frame members 111 arerotatably mounted to the implement frame 103 about a lateral rotationaxis LR oriented substantially parallel to the pivot axes UFA, LFA, URA,LRA and the pivot angle PN is adjusted by rotating the lateral framemember 111 and the front link member 113 attached thereto. A lockmechanism 133 is operative to secure the lateral frame member 111 at aselected rotational position. In the illustrated apparatus 101 thelateral rotation axis LR passes through the front pivot line FPL at amid-point between the upper and lower frame pivot axes UFA, LFA.

FIG. 6 shows the lateral frame member 111 oriented so the front pivotline is oriented at a first pivot angle PNA and the furrow opener 121forms a furrow 123, while FIG. 7 shows the lateral frame member 111oriented so the front pivot line is oriented at a second pivot angle PNBand the furrow opener 121 forms a deeper furrow 123′. The first pivotangle PNA is only three degrees greater than the second pivot angle PNBand results in a furrow depth increase of almost one inch.

FIGS. 6 and 7 also illustrate how the fore and aft presentation angle FNof the furrow opener 121 with respect to the ground surface 107 changesas the pivot angle PN changes. A change in the pivot angle PN causes anequal change in the presentation angle FN. The pivot angle PN decreasesby about three degrees from the pivot angle PNA of FIG. 6 to the pivotangle PNA of FIG. 5 and the presentation angle FN correspondinglyincreases by about three degrees from the presentation angle FNA shownin FIG. 6 to the presentation angle FNB shown in FIG. 7.

The angular relationship between the furrow opener 121 and the groundsurface 107 dictates the form of the furrow 123 made, and therelationship between the furrow opener 121 and a product tube deliveringagricultural products to the furrow 123 dictates the location of theagricultural product in the furrow 123. Thus, the furrow opener 121 mustbe designed to operate satisfactorily within a contemplated range ofpresentation angles FN that the opener will encounter during use.

In a typical seeding operation a desired range of furrow depths might beabout two inches, for example between one half inch to two and one halfinches. The illustrated seeding apparatus 101 could then providesatisfactory operation for furrow openers 121 with a range ofpresentation angle that is plus or minus three degrees. For furrowopeners where the presentation angle is more critical, the presentdisclosure also provides further embodiments described below where thepresentation angle is kept constant as the furrow depth is changed.

FIGS. 8-10 schematically illustrate an alternate apparatus 201 of thepresent disclosure comprising an implement frame 203 mounted on wheels205 for travel over the ground 207 in an operating travel direction T.In the apparatus 201 the wheels 205 support the implement frame 203 at aconstant height above the ground surface 207.

A rockshaft 235 is rotatably attached to a lateral frame member 211 ofthe implement frame 203 about a lateral rotation axis LR, and a lockmechanism 233 is operative to secure the rockshaft 235 at a selectedrotational position.

A plurality of furrow opener assemblies 209 are attached to theimplement frame 203. Each furrow opener assembly 209 extends rearwardfrom the lateral frame member 211 and the rockshaft 235 and each furrowopener assembly 209 comprises two separate parallel arm assemblies.

A frame parallel arm assembly FPAA comprises a front frame link member213F fixed to the lateral frame member 211. In the apparatus 201 thefront frame link member 213F is provided by the link bracket 237extending down from the lateral frame member 211 and the rockshaftbracket 239 mounting the rockshaft 235 to the lateral frame member 211.The link bracket 237 and rockshaft 235 are thus in fixed positions withrespect to each other, and the link bracket 237 defines the lower frontframe pivot axis LFMA and the lateral rotation axis LR provides theupper front frame pivot axis UFMA. A rear frame link member 217F definesupper and lower rear frame pivot axes URMA, LRMA, wherein the framepivot axes are arranged so that a front frame pivot line FFPL betweenthe upper and lower front frame pivot axes UFMA, LFMA and a rear framepivot line RFPL between the upper and lower rear frame pivot axes URMA,LRMA, are parallel and of equal length.

A rockshaft parallel arm assembly RPAA comprises a front rockshaft linkmember 213R fixed to the rockshaft 235 and defining upper and lowerfront rockshaft pivot axes UFSA, LFSA and a rear rockshaft link member217R defining upper and lower rear rockshaft pivot axes URSA, LRSA,wherein the rockshaft pivot axes are arranged so that a front rockshaftpivot line FRPL between the upper and lower front rockshaft pivot axesUFSA, LFSA and a rear rockshaft pivot line RRPL between the upper andlower rear rockshaft pivot axes URSA, LRSA are parallel and of equallength.

A furrow opener bracket 219 is fixed to the rear frame link member 217Fwhich is pivotally attached to the rear rockshaft link member 217R aboutthe upper rear frame axis URMA A. furrow opener 221 is attached to alower portion of the furrow opener bracket 219 and is operative to forma furrow 223 when a bottom end thereof is engaged in the ground 207. Apacker wheel arm 225 is attached to the rear rockshaft link member 217Rand pivotally attached to the rear frame link member 217F about theupper rear frame axis URMA. A packer wheel 227 is rotatably attached toa rear end of the packer wheel arm 225.

A bias element, illustrated as a hydraulic cylinder 229, is operative toexert a downward bias force DBF on the furrow opener assembly 209, and araising mechanism, here provided by the same hydraulic cylinder 229, isoperative to move the furrow opener assembly 209 between the illustratedlowered operating position and a raised transport position indicated bythe raised packer wheel 227R.

The furrow depth of the furrow 223 is adjusted from a first depth shownin FIG. 9 to a second depth shown in FIG. 10 by rotating the rockshaft235 from a first rotational position to a second rotational position,and the illustrated frame and rockshaft parallel arm assemblies maintainthe fore and aft presentation angle FN of the furrow opener at aconstant angle.

In the apparatus 201 the furrow opener bracket 219 is fixed to the rearframe link member 217F and the packer wheel arm 225 is fixed to the rearrockshaft link member 217R, and the rear frame link member 217F ispivotally attached to the rear rockshaft link member 217R about theupper rear frame pivot axis URMA. The front rockshaft link member 213Ris fixed to the rockshaft 235 such that the lateral rotation axis LR islocated on the front rockshaft pivot line FRPL between the upper andlower front rockshaft pivot axes UFSA, LFSA. The upper frame front pivotaxis UFMA coincides with the lateral rotation axis LR, and the rearframe link member 217F is pivotally attached to the rear rockshaft linkmember 217R about the upper rear frame pivot axis URMA at a location onthe rear rockshaft pivot line RRPL between the upper and lower rearrockshaft pivot axes URSA, LRSA corresponding to the location of thelateral rotation axis such that a virtual upper frame arm 215AF isformed between the upper frame front pivot axis UFMA and the upper framerear pivot axis URMA that is parallel to the lower frame arm 215BF.

The rockshaft parallel arm assembly RPAA comprises equal length upperand lower rockshaft arms 215AR, 215BR pivotally attached at front andrear ends thereof to the front and rear rockshaft link members 213R,217R about the corresponding upper and lower front and rear rockshaftpivot axes UFSA, LFSA, URSA, LRSA. In the illustrated furrow openerassembly 209 the frame parallel arm assembly FPAA comprises the virtualupper frame arm 215AF and a lower frame arm 215BF pivotally attached atfront and rear ends thereof to the front and rear frame link members213F, 217F about the corresponding lower front and rear frame pivot axesLFMA, LRMA under the lower rockshaft arm 215BR.

The furrow depth is increased by rotating the rockshaft 235 such thatthe upper front rockshaft pivot axis UFSA is moved forward with respectto the lower front rockshaft pivot axis LFSA, decreasing the pivot anglePN between the front rockshaft pivot line FRPL and the verticalorientation V from the pivot angle PNA shown in FIG. 9 to the lesserangle PNB shown in FIG. 10. Again a three degree difference results in afurrow depth increase of almost an inch. Similarly the furrow depth isdecreased by rotating the rock shaft 235 such that the upper frontrockshaft pivot axis UFSA is moved rearward with respect to the lowerfront rockshaft pivot axis LFSA, increasing the pivot angle PN.

The use of two parallel arm assemblies allows one, in this case therockshaft parallel arm assembly RPAA, to maintain the vertical positionof the furrow opener 221 with respect to the packer wheel 227 constantwhile the other, in this case the frame parallel arm assembly FPAA tomaintain the presentation angle FN constant as rockshaft 235 is rotatedto change the depth of the furrow 223.

FIGS. 11 and 12 schematically illustrate a variation 209′ of the furrowopener assembly 209 shown in FIGS. 8-10. Instead of the furrow openerbracket being fixed to the rear frame link member 217F, a bracket stop241 is fixed to the rear frame link member 217F and the furrow openerbracket 219′ is pivotally attached to the rear rockshaft link member217R about opener pivot axis OPA and is connected during operation tothe rear frame link member 217F by bearing against the bracket stop 241.The furrow opener bracket 219′ extends upward to a top end 243 thereofabove the rear rockshaft link member 217R, and the bias element,illustrated as hydraulic cylinder 229′, exerts a rearward bias force RBFon the top end 243 of the furrow opener bracket 219′ to force the furrowopener bracket 219′ against the bracket stop 241 and to exert thedownward bias force DBF on the top end 243 of the furrow opener bracket219′.

Pressurized hydraulic fluid is directed into a first end 229A of thehydraulic cylinder 229′ to exert the downward bias force DBF andpressurized hydraulic fluid is directed into an opposite second end 229Bof the hydraulic cylinder 229′ such that the hydraulic cylinder 229′exerts a forward force FF on the top end 243 of the furrow openerbracket 219′ which pivots the furrow opener bracket 219′ about theopener pivot axis OPA to the position of FIG. 12 where a raising block245 contacts the packer wheel arm 225 and further forward movement ofthe top end 243 of the furrow opener bracket 219′ raises the furrowopener assembly 209′ to the raised transport position indicated by thepacker wheel 227R. Furrow depth adjustments are made in the same fashionas with the furrow opener assembly 209 by rotating the rockshaft 235.

FIG. 12 also shows a tripped position for the furrow opener bracket 219′such as would occur when the furrow opener encounters an obstructionsuch as a rock that forces the furrow opener bracket 219′ rearwardovercoming the bias force RBF exerted by the hydraulic cylinder 229′. Itwill be understood in this disclosure that various trip mechanisms asare known in the art will typically be incorporated in the furrow openerassemblies to allow the furrow opener to move out of the illustratedoperating positions to a tripped position.

FIGS. 13 and 14 schematically illustrate a further alternate furrowopener assembly 309 comprising frame and rockshaft parallel armassemblies where the furrow opener bracket 319 is fixed to the rearframe link member 317F and the packer wheel arm 325 is pivotallyattached to the rear frame link member 317F and is pivotally attached tothe rear rockshaft link member 317R. The furrow opener assembly 309,like the furrow openers 209, 209′ described above, also maintains aconstant presentation angle FN for the furrow opener 321 while allowingthe furrow depth to be changed by rotating the rockshaft 335.

Here the rockshaft 335 is above the frame parallel arm assembly FPAA.The front rockshaft link member 313R of the rockshaft parallel armassembly RPAA is fixed to the rockshaft 335 such that the lateralrotation LR axis coincides with the lower front rockshaft pivot axisLFSA. The rear frame link member 317F of the frame parallel arm assemblyFPAA extends above the upper parallel arm member 315AF of the frameparallel arm assembly FPAA and is pivotally attached to the rearrockshaft link member 317R about the lower rear rockshaft pivot axisLRSA.

The packer wheel arm 325 comprises an upper packer arm 325A pivotallyattached at a front end thereof to the rear rockshaft link member 317Rabout the upper rear rockshaft pivot axis URSA and a lower packer arm325B pivotally attached to the rear frame link member 317F about thelower rear frame pivot axis LRMA. The upper and lower packer arms 325A,325B are attached at rear portions thereof to each other and rotatablyattached to the packer wheel 327.

The frame parallel arm assembly FPAA comprises equal length upper andlower frame arms 315AF, 315BF pivotally attached at front and rear endsthereof to the front and rear frame link members 313F, 317F about thecorresponding upper and lower front and rear frame pivot axes UFMA,LFMA, URMA, LRMA.

The rockshaft parallel arm assembly RPAA comprises an upper rockshaftarm 315AR pivotally attached at front and rear ends thereof to the frontand rear rockshaft link members 313R, 317R about the corresponding upperfront and rear rockshaft pivot axes UFSA, URSA, and a virtual lowerrockshaft arm 315BR that is formed between the front lower rockshaftpivot axis LFSA and the lower rockshaft rear pivot axis LRSA.

Here the rear frame link member 317F of the frame parallel arm assemblyFPAA maintains the furrow opener bracket 319 attached thereto, and thusthe furrow opener 321, at a constant presentation angle FN with respectto the ground 307. The rear frame link member 317F is also attached tothe rear rockshaft link member 317R and so maintains the packer wheel327 and furrow opener 321 at a constant vertical relationship, which canbe changed by rotating the rockshaft 335 to change the pivot angle PNbetween the front rockshaft pivot line FRPL and the vertical orientationV.

With the rockshaft 335 fixed at a first fixed rotation position shown inFIG. 13 with the pivot angle PNA, the furrow depth is DA. Rotating therockshaft 335 to a second fixed rotation position shown in FIG. 14 withthe pivot angle increased to pivot angle PNB, the furrow depth isdecreased to DB. It can be seen that increasing the pivot angle PN movesthe packer wheel 337 down with respect to the furrow opener 321 and thusreduces the depth of the furrow 323.

The present disclosure further provides a method of forming a furrow 23in a ground surface 7. The method comprises connecting a front linkmember 13 of a parallel arm assembly to a lateral frame member 11 of animplement frame 3 mounted on wheels 5 for travel over the ground surface7 in an operating travel direction such that the parallel arm assemblyextends rearward from the lateral frame member 11; wherein a front pivotline FPL connects upper and lower front pivot axes UFA, LFA of theparallel arm assembly and is substantially parallel to a rear pivot lineRPL connecting upper and lower rear pivot axes URA, LRA of the parallelarm assembly, and the front and rear pivot lines FPL, RPL are orientedat a pivot angle PN with respect to a vertical orientation V; connectinga furrow opener bracket 19 to a rear link member 17 of the parallel armassembly, and attaching a furrow opener 21 to a lower portion of thefurrow opener bracket 19, wherein the furrow opener 21 is operative toform the furrow 23 when a bottom end thereof is engaged in the groundsurface 7; supporting the rear link member 17 with a packer wheel 27rearward of the furrow opener 21; exerting a downward bias force DBF onthe parallel arm assembly such that the furrow opener 21 engages theground surface 7; moving the implement frame 3 across the ground surface7 to create the furrow 23; orienting the pivot angle PN at a first pivotangle PNA to form the furrow with a first furrow depth, and orientingthe pivot angle PN at a second pivot angle PNB to form the furrow with asecond furrow depth different from the first furrow depth.

In one embodiment the method comprises rigidly attaching the front linkmember 13 to the lateral frame member 11, and attaching the furrowopener bracket 19 and the packer wheel 27 to the rear link member 17such that during operation the rear link member 17, the furrow opener21, and the packer wheel 27 are in fixed positions with respect to eachother.

In the illustrated furrow opener assembly 9 of the seeding apparatus 1the upper front pivot axis UFA moves rearward with respect to the lowerfront pivot axis LFA when the pivot angle PN changes from the firstpivot angle PNA to the second pivot angle PNB, and the first furrowdepth is greater than the second furrow depth. Similarly the upper frontpivot axis UFA moves forward with respect to the lower front pivot axisLFA when the pivot angle PN changes from the second pivot angle PNB tothe third pivot angle PNC, and wherein the second furrow depth is lessthan the third furrow depth.

The method can comprise changing the pivot angle PN by raising andlowering a front end 3F of the implement frame 3 with respect to a rearend 3 r of the implement frame 3 as schematically illustrated in FIGS.2-4. Alternately the method can comprise rotatably mounting the lateralframe member 111 to the implement frame 103 about a lateral rotationaxis LR oriented substantially parallel to the front and rear pivot axesUFA, LFA, URA, LRA and changing the pivot angle PN by rotating thelateral frame member 111 about the lateral rotation axis LR asschematically illustrated in FIGS. 6 and 7.

The method of forming a furrow in a ground surface 207 can furthercomprise rotatably mounting a rockshaft 235 to the implement frame 203about a lateral rotation axis LR as schematically illustrated in thefurrow opener assembly 209 of FIGS. 9 and 10 comprising a frame parallelarm assembly FPAA and a rockshaft parallel arm assembly RPAA. The furrowopener bracket 219 is pivotally attached to the rear rockshaft linkmember 217R and connected during operation to the rear frame link member271F. A packer wheel arm 225 is connected to the rear frame link member217F and the rear rockshaft link member 217R and the packer wheel 227 isrotatably attached to a rear end of the packer wheel arm 225. Exertingthe downward bias force DBF on the parallel arm assembly causes thefurrow opener 221 to engage the ground surface 207 as the implementframe 203 moves across the ground surface 207, and orienting the pivotangle PN at a first pivot angle PNA forms the furrow 223 with a firstfurrow depth, and orienting the pivot angle PN at a second pivot anglePNB forms the furrow 223 with a second furrow depth different from thefirst furrow depth. The method includes configuring the furrow openerassembly 209 to maintain a fore and aft presentation angle FN of thefurrow opener 221 with respect to the ground at a constant angle as therockshaft pivot angle PN changes.

In the furrow opener assembly 209, the method comprises fixing thepacker wheel arm 225 to the rear rockshaft link member 217R, andpivotally attaching the rear frame link member 217F to the rearrockshaft link member 217R; fixing the front rockshaft link member 213Rto the rockshaft 235 such that the lateral rotation axis LR is locatedon the front rockshaft pivot line FRPL midway between the upper andlower front rockshaft pivot axes UFSA, LFSA; configuring the front framelink member 213F such that the upper frame front pivot axis UFMAcoincides with the lateral rotation axis LR; and pivotally attaching therear frame link member 217F to the rear rockshaft link member 217R aboutthe upper rear frame pivot axis URMA at a location on the rear rockshaftpivot line RRPL midway between the upper and lower rear rockshaft pivotaxes URSA, LRSA such that a virtual upper frame arm 215AF is formedbetween the upper frame front pivot axis UFMA and the upper frame rearpivot axis URMA.

As schematically illustrated in the furrow opener assembly 209′ of FIGS.11 and 12, the method can also comprise fixing a bracket stop 241 to therear frame link member 217F and pivotally attaching the furrow openerbracket 219′ to the rear rockshaft link member 217R and during operationconnecting the furrow opener bracket 219′ to the rear frame link member217F by forcing the furrow opener bracket 219′ against the bracket stop241; and during operation fixing the packer wheel 227 in a fixedposition with respect to the rear rockshaft link member 217R. The furrowopener bracket 219′ extends upward to a top end 243 thereof above therear rockshaft link member 217R, and a hydraulic cylinder 229′ exerts abias force RBF rearward and downward on the top end 243 of the furrowopener bracket 219′ to force the furrow opener bracket 219′ against thebracket stop 241 and to exert the downward bias force DBF on the top end243 of the furrow opener bracket 219′. Pressurized hydraulic fluid isdirected into a first end 229A of the hydraulic cylinder 229′ to exertthe downward bias force DBF and pressurized hydraulic fluid is directedinto an opposite second end 229B of the hydraulic cylinder 229′ to movethe furrow opener assembly 209′ to the raised transport position.

FIGS. 13 and 14 schematically illustrate a further method of forming afurrow in a ground surface by rotatably mounting a rockshaft 335 to theimplement frame about a lateral rotation axis LR and using both a frameparallel arm assembly FPAA and a rockshaft parallel arm assembly RPAA.The method comprises pivotally attaching the packer wheel arm 325 to therear frame link member 317F and to the rear rockshaft link member 317R;positioning the rockshaft 335 above the frame parallel arm assembly;fixing the front rockshaft link member 313R to the rockshaft 335 suchthat the lateral rotation axis LR coincides with the lower frontrockshaft pivot axis LFSA; extending the rear frame link member 317Fabove the frame parallel arm assembly FPAA and pivotally attaching a topend 343 thereof to the rear rockshaft link member 317R about the lowerrear rockshaft pivot axis LRSA; and configuring the packer wheel arm 325to comprise an upper packer arm 325A pivotally attached at a front endthereof to the rockshaft link member 317R about the upper rear rockshaftpivot axis URSA and a lower packer arm 325B pivotally attached about thelower rear frame pivot axis LRMA to the rear frame link member 317F, andwherein the upper and lower packer arms 325A, 325B are attached at rearportions thereof to each other. The method includes configuring thefurrow opener assembly 309 to maintain a fore and aft presentation angleFN of the furrow opener 321 with respect to the ground 307 at a constantangle as the rockshaft pivot angle PN changes.

The present disclosure provides a seeding apparatus with trailing armfurrow opener assemblies where the depth of the furrow formed by thefurrow openers can be quickly changed to suit different crops and soilconditions. The depth of penetration of all the furrow openers on aseeding implement can be adjusted at the same time. In some embodimentsthe presentation angle of the furrow opener with respect to the groundsurface can be maintained at a constant desired angle.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous changes and modifications willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly, all such suitable changes or modificationsin structure or operation which may be resorted to are intended to fallwithin the scope of the claimed invention.

What is claimed is:
 1. A method of forming a furrow in a ground surface,the method comprising: connecting a front link member of a parallel armassembly to a lateral frame member of an implement frame mounted onwheels for travel over the ground surface in an operating traveldirection such that the parallel arm assembly extends rearward from thelateral frame member; wherein a front pivot line connects upper andlower front pivot axes of the parallel arm assembly and is substantiallyparallel to a rear pivot line connecting upper and lower rear pivot axesof the parallel arm assembly, and the front and rear pivot lines areoriented at a pivot angle with respect to a vertical orientation;connecting a furrow opener bracket to a rear link member of the parallelarm assembly, and attaching a furrow opener to a lower portion of thefurrow opener bracket, wherein the furrow opener is operative to formthe furrow when a bottom end thereof is engaged in the ground surface;supporting the rear link member with a packer wheel rearward of thefurrow opener; exerting a downward bias force on the parallel armassembly such that the furrow opener engages the ground surface; movingthe implement frame across the ground surface to create the furrow;orienting the pivot angle at a first pivot angle to form the furrow witha first furrow depth, and orienting the pivot angle at a second pivotangle to form the furrow with a second furrow depth different from thefirst furrow depth; and rigidly attaching the front link member to thelateral frame member, and attaching the furrow opener bracket and thepacker wheel to the rear link member such that during operation the rearlink member, the furrow opener, and the packer wheel are in fixedpositions with respect to each other.
 2. The method of claim 1 whereinthe upper front pivot axis moves rearward with respect to the lowerfront pivot axis when the pivot angle changes from the first pivot angleto the second pivot angle, and wherein the first furrow depth is greaterthan the second furrow depth.
 3. The method of claim 1 wherein the upperfront pivot axis moves forward with respect to the lower front pivotaxis when the pivot angle changes from the first pivot angle to thesecond pivot angle, and wherein the first furrow depth is less than thesecond furrow depth.
 4. The method of claim 1 comprising changing thepivot angle by raising and lowering a front end of the implement framewith respect to a rear end of the implement frame.
 5. The method ofclaim 1 comprising rotatably mounting the lateral frame member to theimplement frame about a lateral rotation axis oriented substantiallyparallel to the front and rear pivot axes and changing the pivot angleby rotating the lateral frame member about the lateral rotation axis. 6.The method of claim 1 comprising: rotatably mounting a rockshaft to theimplement frame about a lateral rotation axis oriented substantiallyparallel to the front and rear pivot axes, and securing the rockshaft ata selected rotational position; providing a furrow opener assemblyextending rearward from the lateral frame member and the rockshaft, thefurrow opener assembly comprising: a frame parallel arm assemblycomprising a front frame link member fixed to the lateral frame memberand defining upper and lower front frame pivot axes, and a rear framelink member defining upper and lower rear frame pivot axes, andarranging the frame pivot axes so that a front frame pivot line betweenthe upper and lower front frame pivot axes and a rear frame pivot linebetween the upper and lower rear frame pivot axes are substantiallyparallel and of substantially equal length; a rockshaft parallel armassembly comprising a front rockshaft link member fixed to the rockshaftand defining upper and lower front rockshaft pivot axes and a rearrockshaft link member defining upper and lower rear rockshaft pivotaxes, wherein the rockshaft pivot axes are arranged so that a frontrockshaft pivot line between the upper and lower front rockshaft pivotaxes and a rear rockshaft pivot line between the upper and lower rearrockshaft pivot axes are substantially parallel and of substantiallyequal length, and wherein the front and rear rockshaft pivot lines areoriented at a rockshaft pivot angle with respect to a verticalorientation; wherein the furrow opener bracket is pivotally attached tothe rear rockshaft link member and connected during operation to therear frame link member, and a packer wheel arm is connected to the rearframe link member and the rear rockshaft link member and the packerwheel is rotatably attached to a rear end of the packer wheel arm;exerting the downward bias force on the on the furrow opener assembly;securing the rockshaft at a first selected rotational position to orientthe rockshaft pivot angle at a first rockshaft pivot angle to form thefurrow with the first furrow depth, and securing the rockshaft at asecond selected rotational position to orient the rockshaft pivot angleat a second rockshaft pivot angle to form the furrow with the secondfurrow depth; and configuring the furrow opener assembly to maintain afore and aft presentation angle of the furrow opener with respect to theground at a constant angle as the rockshaft pivot angle changes.
 7. Themethod of claim 6 wherein the upper front rockshaft pivot axis movesrearward with respect to the lower front rockshaft pivot axis when therockshaft pivot angle changes from the first rockshaft pivot angle tothe second rockshaft pivot angle, and wherein the first furrow depth isgreater than the second furrow depth.
 8. The method of claim 6 whereinthe upper front rockshaft pivot axis moves forward with respect to thelower front rockshaft pivot axis when the rockshaft pivot angle changesfrom the first pivot angle to the second pivot angle, and wherein thefirst furrow depth is less than the second furrow depth.
 9. The methodof claim 6 comprising fixing the packer wheel arm to the rear rockshaftlink member, and pivotally attaching the rear frame link member to therear rockshaft link member.
 10. The method of claim 9 comprising: fixingthe front rockshaft link member to the rockshaft such that the lateralrotation axis is located on the front rockshaft pivot line midwaybetween the upper and lower front rockshaft pivot axes; configuring thefront frame link member such that the upper frame front pivot axiscoincides with the lateral rotation axis; pivotally attaching the rearframe link member to the rear rockshaft link member about the upper rearframe pivot axis at a location on the rear rockshaft pivot line midwaybetween the upper and lower rear rockshaft pivot axes such that avirtual upper frame arm is formed between the upper frame front pivotaxis and the upper frame rear pivot axis.
 11. The method of claim 10wherein: the rockshaft parallel arm assembly comprises equal lengthupper and lower rockshaft arms pivotally attached at front and rear endsthereof to the front and rear rockshaft link members about thecorresponding upper and lower front and rear rockshaft pivot axes; theframe parallel arm assembly comprises the virtual upper frame arm and alower frame arm pivotally attached at front and rear ends thereof to thefront and rear frame link members about the corresponding lower framefront and rear pivot axes under the lower rockshaft arm.
 12. The methodof claim 6 comprising fixing a bracket stop to the rear frame linkmember and pivotally attaching the furrow opener bracket to the rearrockshaft link member and during operation connecting the furrow openerbracket to the rear frame link member by forcing the furrow openerbracket against the bracket stop; and during operation fixing the packerwheel in a fixed position with respect to the rear rockshaft linkmember.
 13. The method of claim 12 wherein: the front rockshaft linkmember is fixed to the rockshaft such that the lateral rotation axis islocated on the front rockshaft pivot line midway between the upper andlower front rockshaft pivot axes; the upper frame front pivot axiscoincides with the lateral rotation axis, and the rear frame link memberis pivotally attached to the rear rockshaft link member about the upperrear frame pivot axis at a location on the rear rockshaft pivot linemidway between the upper and lower rear rockshaft pivot axes such that avirtual upper frame arm is formed between the upper frame front pivotaxis and the upper frame rear pivot axis.
 14. The method of claim 13wherein: the rockshaft parallel arm assembly comprises equal lengthupper and lower rockshaft arms pivotally attached at front and rear endsthereof to the front and rear rockshaft link members about thecorresponding upper and lower front and rear rockshaft pivot axes; theframe parallel arm assembly comprises the virtual upper frame arm and alower frame arm pivotally attached at front and rear ends thereof to thefront and rear frame link members about the corresponding lower framefront and rear pivot axes under the lower rockshaft arm.
 15. The methodof claim 14 wherein the furrow opener bracket extends upward to a topend thereof above the rear rockshaft link member, and a bias element isoperative to exert a bias force rearward and downward on the top end ofthe furrow opener bracket to force the furrow opener bracket against thebracket stop and to exert the downward bias force on the top end of thefurrow opener bracket.
 16. The method of claim 15 wherein the biaselement comprises a hydraulic cylinder and wherein pressurized hydraulicfluid is directed into a first end of the hydraulic cylinder to exertthe downward bias force and pressurized hydraulic fluid is directed intoan opposite second end of the hydraulic cylinder to move the furrowopener assembly to the raised transport position.
 17. The method ofclaim 6 comprising pivotally attaching the packer wheel arm to the rearframe link member and to the rear rockshaft link member.
 18. The methodof claim 17 comprising: positioning the rockshaft above the frameparallel arm assembly; fixing the front rockshaft link member to therockshaft such that the lateral rotation axis coincides with the lowerfront rockshaft pivot axis; extending the rear frame link member abovethe frame parallel arm assembly and pivotally attaching a top endthereof to the rear rockshaft link member about the lower rear rockshaftpivot axis; configuring the packer wheel arm to comprise an upper packerarm pivotally attached at a front end thereof to the rear rockshaft linkmember and a lower packer arm pivotally attached to the rear frame linkmember, and wherein the upper and lower packer arms are attached at rearportions thereof to each other.
 19. The method of claim 18 wherein: theframe parallel arm assembly comprises equal length upper and lower framearms pivotally attached at front and rear ends thereof to the front andrear frame link members about the corresponding upper and lower frontand rear frame pivot axes; the rockshaft parallel arm assembly comprisesan upper rockshaft arm pivotally attached at front and rear ends thereofto the front and rear rockshaft link members about the correspondingupper front and rear rockshaft pivot axes, and a virtual lower rockshaftarm that is formed between the lower front rockshaft pivot axis and thelower rockshaft rear pivot axis.
 20. The method of claim 19 wherein theupper packer arm is pivotally attached at the front end thereof to therear rockshaft link member about the upper rear rockshaft pivot axis,and the lower packer arm is pivotally attached to the rear frame linkmember about the lower rear frame pivot axis.